Methylprednisolone Does Not Enhance Paraoxonase 1 Activity During Cardiopulmonary Bypass Surgery—A Randomized, Controlled Clinical Trial

•CPB leads to inflammatory responses and oxidative stress.•PON1 is decreased in systemic inflammation and ischemia, like that during CPB is.•Glucocorticoids counteract oxidative stress by up regulating PON1 gene expression.•Methylprednisolone doesn't have significant effects on PON1 activity during CPB. Cardiopulmonary bypass (CPB) is linked to systemic inflammatory responses and oxidative stress. Paraoxonase 1 (PON1) is an antioxidant enzyme with a cardioprotective role whose activity is decreased in systemic inflammation and in patients with acute myocardial and global ischemia. Glucocorticoids counteract the effect of oxidative stress by upregulating PON1 gene expression. The authors aimed to determine the effect of methylprednisolone on PON1 activity during cardiac surgery on CPB. Prospective, randomized, controlled clinical trial. The University Medical Center Ljubljana, Slovenia. Forty adult patients who underwent complex cardiac surgery on CPB between February 2016 and December 2017 were randomized into methylprednisolone and control groups (n = 20 each). Patients in the methylprednisolone group received 1 g of methylprednisolone in the CPB priming solution, whereas patients in the control group were not given methylprednisolone during CPB. The effect of methylprednisolone from the CPB priming solution was compared with standard care during CPB on PON1 activity until postoperative day 5. Correlations of PON1 activity with lipid status, mediators of inflammation, and hemodynamics were analyzed also. No significant differences were found between study groups for PON1 activity, high-density lipoprotein, and low-density lipoprotein in any of the measurement intervals (p > 0.016). The methylprednisolone group had significantly lower tumor necrosis factor alpha (p < 0.001) and interleukin-6 (p < 0.001), as well as C-reactive protein and procalcitonin (p < 0.016) after surgery. No significant difference was found between groups for hemodynamic parameters. A positive correlation existed between PON1 and lipid status, whereas a negative correlation was found between PON1 activity and tumor necrosis factor alpha, interleukin-6, and CPB duration. Methylprednisolone does not influence PON1 activity during cardiac surgery on CPB.